The history of the New York State United Teachers (NYSUT) and its relationship with the National Education Association (NEA) and the American Federation of Teachers (AFT) sheds some light on the most recent failed attempt of the NEA and the AFT to merge. The merger, in 1972, of NEA's New York State Teachers Association with the AFT's New York State Federation into the NYSUT represented the largest merger agreement in teacher union history and anticipated the prospect of a merged national teachers union. The factors influencing the New York merger and the ensuing experiences with the disaffiliation of some NEA locals provide insights into the problems and obstacles a merged national organization may have to overcome. In particular, the AFT is committed to a highly disciplined political structure based on a strong, centralized caucus system, relying on a leadership cadre to formulate policies which they disseminate downward to the membership. This structure, which also became dominant in the NYSUT, stands in contrast to the more open, decentralized organization of the NEA, which allows for secret ballot to determine association policy, proportional representation, and term limits. A merger of the NEA and AFT would not guarantee the adoption of the latter's caucus and governance system since the NEA is two and one half times larger than the AFT; however, based on the New York experience, the discipline and focus of the AFT could significantly influence the structure of the new organization. Given the divergent histories and commitments of the two organizations, the nature of democratic governance is the key issue that must be resolved if an NEA-AFT merger is to succeed. References are provided in footnotes. (ND)